Did You Spot Conan O'Brien's Sister in The Fighter?

In The Fighter, Mark Wahlberg and Christian Bale claim the most screen time, but there's no denying their slew of sisters' scene-stealing abilities.

What you might not have realized is that one of the Eklund women has a famous brother in real life, too. Kate O'Brien, sister to late night TV host Conan O'Brien, plays Phyllis "Beaver" Eklund in her acting debut.

"I work at a school and someone said, 'They're casting [The Fighter], you should go down, you look Irish Catholic,' " Kate O'Brien told PEOPLE. "I'm one of six, so it wasn't that hard for me to look like I might have more siblings [in the movie]."